Four of the seven deaths happened after encounters with police. But in the best-known case, the 2014 shooting of 18-year-old Michael Brown in Ferguson, Missouri, the Justice Department found that the evidence supported the officer, Darren Wilson, who said Brown punched him and tried to grab his gun.
In the other three cases, police either clearly or arguably used excessive force. The clearest example of unnecessary force involved Sandra Bland, who was found dead, apparently by suicide, in a Texas jail last year, three days after Trooper Brian Encinia pulled her over for changing lanes without signaling.
Dashcam video of the traffic stop showed Encinia lost his temper and needlessly escalated the situation, leading to an arrest that should never have happened. Encinia was fired after a grand jury indicted him for lying in his report on the incident.
Eric Garner died of a heart attack in 2014 after he was tackled by New York City cops trying to arrest him for selling untaxed cigarettes. Video of the encounter showed that Garner, whose death was classified as a homicide, repeatedly complained that he could not breathe. A grand jury declined to indict Daniel Pantaleo, an officer who used what looked like a prohibited chokehold, in connection with Garner's death.
In 2014, a Milwaukee police officer, Christopher Manney, took out his baton after Dontre Hamilton resisted a pat-down in a public park. Hamilton grabbed the baton and hit Manney in the neck, and Manney shot Hamilton 14 times. Although the district attorney concluded that Manney had acted in self-defense, the police chief fired him because the pat-down that culminated in the shooting was not justified by reasonable suspicion.
Two other cases highlighted at the convention on Tuesday involved unarmed black teenagers shot by private citizens. But the details of the incidents were very different, and so were the legal outcomes.
In 2013, George Zimmerman, a neighborhood watch volunteer in Sanford, Florida, was acquitted of manslaughter and second-degree murder in the 2012 shooting of 17-year-old Trayvon Martin. Physical evidence and witness testimony supported Zimmerman's claim that he acted in self-defense after Martin knocked him down, pinned him, and began knocking his head against the pavement.
In 2014, by contrast, Michael Dunn was convicted of murdering 17-year-old Jordan Davis after an argument over loud music at a Jacksonville gas station in 2012. Dunn's implausible self-defense claim was based on a shotgun that was never recovered and no one else saw.
Contrary to what gun control supporters typically claim, neither of these cases hinged on Florida's "stand your ground" self-defense law, which eliminated the duty to retreat for people attacked in public places. Even in states that impose a duty to retreat, Zimmerman and Dunn could have mounted the same legal defenses with the same results.
Gun control supporters also have latched onto the seventh case mentioned on Tuesday night: the 2013 shooting of 15-year-old Hadiya Pendleton at a Chicago park by a teenager who mistook one of her companions for a rival gang member. While Hadiya's death was senseless and horrifying, none of the new gun restrictions that Democrats advocate in her name would have prevented it.
The use of excessive force by police, regardless of the victim's race, should trouble everyone. So should the racially skewed experiences with cops documented by scholars such as Harvard economist Roland Fryer and University of North Carolina political scientist Frank Baumgartner.
Activists undermine these important causes when they ignore plausible self-defense claims, perpetuate misconceptions about "stand your ground" laws, and push a divisive gun control agenda. As President Obama likes to say, equal treatment under the law is "an American issue," or at least it should be.